AP1000 Nuclear Power Plant
Terry L. Schulz Consulting Engineer Westinghouse Electric Company, LLC (412) 374-5120 [email protected] July 22, 2008
Westinghouse Proprietary Class II AP1000 Outline
• Introduction • Advanced Reactor Design Background • Overview of AP1000 Plant Design • AP1000 Passive Safety Systems • AP1000 Non-safety Defense-in-Depth Systems • AP1000 Safety Analysis/PRA • AP1000 ... Ready for Commercialization
Slide 2 AP1000 … Westinghouse Standard Plant
• Simple
• Safe
• Mature
• Affordable
• Contracted
Slide 3 AP1000 Investment in Technology
Simplified Passive Extensive Safety Testing of Proven Systems Passive Advanced Safety Design Systems Features
US NRC Certified Modular Construction
REACTOR VESSEL PRA and
REACTOR VESSEL STEAM VENTS SUPPORT STEEL Severe TYPICAL 4 PLACES Accident CORE Mitigation SHIELD WALL
Features INSULATION Reduced Components Short Construction Schedule WATER INLET and Commodities
Slide 4 AP1000 Major Uprate of AP600
• Design Approach – Increase the capability/capacity within “space constraints” of AP600 – Retain design and regulatory bases for Advanced Passive Plants – Retain credibility of “proven components” – Retain AP600 plant design (footprint); largely preserves detailed design investment – Retain the basis for the cost estimate, construction schedule and modularization scheme
Slide 5 Comparison of Selected Parameters
Parameter Doel 4/Tihange 3 AP1000 (3 SG / RCPs) (2 SG / 4 RCPs) Net Electric Output, MWe 985 1117 Reactor Power, MWt 2988 3400 Hot Leg Temperature, oF (oC) 626 (330) 610 (321) Number of Fuel Assemblies 157 157 Type of Fuel Assembly 17x17 17x17 Active Fuel Length, ft (m) 14 (4.27) 14 (4.27) Linear Hear Rating, kw/ft 5.02 5.71 Control Rods / Gray Rods 52 / 0 53 / 16 R/V I.D., in. (m) 157 (3.99) 157 (3.99) Vessel Flow, gpm (m3/hr) x103 295.5 (67.1) 300 (68.1) SG Surface Area ea., ft2 (m2) x 103 68 (6.3) 125 (11.1) Pressurizer Volume, ft3 (m3) 1400 (39.6) 2100 (59.5)
Slide 6 Overview of AP1000 Plant Design
Slide 7 AP1000 Design Overview
• For the Power Generation Function, AP1000 is a typical Westinghouse PWR with advances in materials and components - Fuel, Reactor Vessel, Reactor Coolant Loop - Steam Generators, Reactor Coolant Pumps, Turbine, Plant Controls • Reactor Safety Functions are achieved without using any safety- related AC power - Valve Actuations (fail safe, battery powered) - Condensation, Natural Circulation, Evaporation, Compressed Gasses • Actuation of Passive Safety Systems is by simple, reliable changes in valve positions. • System performance has been proven by extensive testing approved by the NRC
Slide 8 AP1000 Design Features
• Integrated Power Plant Design • Proven Power-Producing Components (Reactor, Fuel, etc) • Simplified RCS Loops with Canned Motor Pumps • Simplified Passive Safety Systems • Simplified Non-safety Defense-In-Depth (DID) Systems • Microprocessor, Digital Technology Based I&C • Compact Control Room, Electronic Operator Interface • Optimized Plant Arrangement – Construction, Operation, Maintenance, Safety, Cost • Extensive Use of Modular Construction – 3-Year Construction Schedule (first concrete pour to HFT)
Slide 9 Proven AP1000 Major Components
• Fuel, Internals, Reactor Vessel – Similar to Doel 4, Tihange 3, S. Texas – No bottom-mounted instrumentation – Improved materials - 60 year life • Steam Generators – Similar to large W/CE SGs in operation • System 80, ANO RSG • Reactor Coolant Pumps – Canned motor pumps, no shaft seals • Early commercial reactors (Shippingport, Yankee Rowe) • Simplified Main Loop – Reduces welds 67%, supports 90% • Pressurizer – 50% larger than operating plants
Slide 10 AP1000 Core Design
• AP1000 Core Design Features – Higher power density – 18 month cycles – Initial and equilibrium cycle designs presented in Design Control Document – Normal BLACK rods for operation – New GRAY rod configuration • Load follow / rapid power reduction • No boron changes required
Slide 11 Reactor Coolant Pump
• Based on Field-Proven, Canned Motor Pumps – No shaft seals • No seal injection / leakoff system • No seal leakage / failure – Water lubricated bearings • No oil lubricating system • Eliminates fire protection issues – Compact, high inertia flywheels • Upper and lower • Inservice inspection not required – No services required in accident • Tripped to allow CMT operation – No planned maintenance
Slide 13 AP1000 Reactor Coolant System
M M
M M IRWST
M M M M
M M IRWST
M M
PRESSURIZER
PRHR HX
M CMT B / CVS ACC B CMT B PURIF M RNS
RCP 1A M RCP 2B
M
PRHR SG 1 RV SG 2 HX
RCP 1B RNS RCP 2A
RNS
CMT A / CMT A ACC A
Slide 14 AP1000 Passive Safety Systems
Slide 15 AP1000 Approach to Safety • Passive Safety-Related Systems – Use “passive” process only, no active pumps, diesels, …. • One time alignment of valves • No support systems required after actuation – No AC power, cooling water, HVAC, I&C – Greatly reduced dependency on operator actions – Mitigate design basis accidents without nonsafety systems – Meet NRC PRA safety goals without use of nonsafety systems • Active Nonsafety-Related Systems – Reliably support normal operation • Redundant equipment powered by onsite diesels – Minimize challenges to passive safety systems – Not required to mitigate design basis accidents
Slide 16 Passive Systems Greatly Simplify Safety Systems
Standard PWR AP1000
Slide 17 Passive Safety Features
• Passive Residual Heat Removal – Natural circulation HX connected to RCS • Passive Safety Injection – Natural circulation / gravity drain core makeup tanks (RCS pres)
–N2 pressurized accumulators (700 psig) – Gravity drain refueling water storage tank (containment pres) – Automatic depressurization valves, Pressurizer and RCS hot leg • Passive Containment Cooling – Natural circulation of air / evaporation of water on outside surface of steel containment vessel
Slide 18 Passive Safety Features (cont’d)
• Passive Radiation Removal from Containment Atm. – Natural circulation / removal mechanisms • Passive Main Control Room Habitability – Compressed air pressurization of MCR • Passive MCR / I&C Room Cooling – Natural circulation to concrete walls / ceiling • Passive Containment pH Control – Baskets of TSP flooded by accident
Slide 19 AP1000 Passive Core Cooling System • Passive RHR Heat Exchanger (PRHR HX) – Natural circ. heat removal • Passive Safety Injection – Core Makeup Tanks • Full RCS pres, natural circ. inject • Replaces HHSI pumps – Accumulators • Similar to current plants – IRWST Injection • Low pressure (replaces LHSI pumps) – Containment Recirculation • Gravity recirc. (replaces pumped recirc) – Automatic RCS Depressurization • Staged, controlled depressurization • Stages 1-3 to IRWST, stage 4 to containment
Slide 20 Passive Core Cooling System at Work
Slide 21 Passive Decay Heat Removal
CONTAINMENT VENTS CONDENSATE M PRESSURIZER
OVERFLOW STEAM LINE – Normally Isolated By
Two AOV, Fail Open STEAM PRHR IRWST GEN. HX FEEDWATER • Opening 1 AOV LINE actuates RCS cooling via natural circulation
• AOVs actuated by PMS ADS FO STAGES and by DAS 4-A
4-C – IRWST Absorbs Heat CL • Takes ~ 2 hr to heat up HL RCP
to saturated REACTOR CORE VESSEL • Steam is condensed by PCS and returned to IRWST by gutter
Slide 22 Passive Safety Injection
M #1 M
ADS
M #2 M STAGES 1-3 (1 OF 2) CONTAINMENT
M #3 M REFUEL CAVITY CORE MAKEUP
M TANK (1 OF 2) SPARGERS (1 OF 2)
PRESSURIZER PRHR HX
IRWST IRWST SCREEN M (1 OF 2)
LOOP FAI
COMPART. M M M RECIRC FO SCREEN ADS (1 OF 2) STAGE 4 ACCUM. (1 OF 2) RNS (1 OF 2) PUMPS
N2
CL HL
• Uses One Time Valve Alignment DVI CONN. (1 OF 2) RNS CORE M – Accum uses check valves PUMPS – CMT uses fail open AOV REACTOR VESSEL – ADS uses MOV for 1/2/3 & Squibs for 4 – IRWST uses Squibs and check valves
Slide 23 LOCA Long Term Cooling
– Uses No Pumps – Addresses Debris Head Loss Issues • No fiber generation • Large advanced design screens – Demonstrated by test • Low flows, deep flood up –Low velocities • Delayed start of recirculation
Slide 24 Passive Containment Cooling System
• PCS Water Storage Tank – Provides 72 hr drain
AIR EXHAUST • Afterwards use on/offsite water PCCWST • Air only cooling prevents failure
FO M
FO M – Flow decreases with time M M • 4 standpipes control flow BAFFLE • PCS Flow Rates AIR INLET – High initial flow
CONTAINMENT OFFSITE SHELL SUPPLY • Rapidly forms water film • Effectively reduces cont pressure FIRE NORMAL / SYSTEM ANCILLARY MAKEUP – Later flows match decay heat • 3 Redundant Drain Paths
STORM STORM –2 AOV, 1 MOV DRAINS DRAINS – Improves PRA reliability • T&H uncertainty of cont cooling without water drain
Slide 25 Passive Containment Cooling System at Work
Slide 26 AP1000 Most Tested Reactor
Slide 27 AP1000 Safety Analysis
• Safety Analysis Performed
– Computer codes were verified • Adequate to model passive systems • Verified against extensive AP600 tests – Tests well scaled for AP600 and AP1000 • NRC / ACRS reviewed tests and computer code verification
– Extensive accident analysis were performed • Range of Design Basis Accident conditions, single failures • NRC / ACRS reviewed and approved results
Slide 28 Westinghouse Uses PRA as Design & Licensing Tool
• 7 Major PRA Quantifications Performed on AP600 – First in 1987, final in 1997 – Extensive interaction with plant designers • Changes were made to analysis, procedures and design • Used to guide severe accident design, ensures reliability – Extensive NRC review / comment • 4 Major PRA Quantifications Performed on AP1000 – Started with AP600 models / analysis – Benefited from AP600 development and NRC review – Modified models to account for the few changes from AP600 – Extensive NRC review / comment
Slide 29 AP1000 Provides Safety and Investment Protection
AP1000 U. S. NRC Current Utility Results Requirements Plants Requirements
1 x 10-4 (a) 5 x 10-5 <1 x 10-5 (a) 5.1 x 10-7 (a) Core Damage Frequency per Year Note (a) CDF includes random and internal hazard events from at-power and shutdown conditions.
Slide 30 Severe Accidents Addressed
• Core-Concrete Interaction – Ex-vessel cooling retains damaged core – Tests and analysis of IVR reviewed by U.S. NRC – Prevents core-concrete interaction • High Pressure Core Melt – Eliminated by redundant, diverse ADS • Hydrogen Detonation – Prevented by redundant, diverse igniters and passive autocatalytic recombiners • Steam Explosions – Prevented by IVR
Slide 31 Severe Accident Design at Work
Slide 32 AP1000 Non-Safety Defense-In-Depth Systems
Slide 33 AP1000 Active Nonsafety Features
• Active Nonsafety Functions – Reliably support normal operation – Minimize challenge to passive safety systems – Not required to mitigate design basis accidents – Not required to meet NRC safety goals • Active Nonsafety Design Features – Simplified designs (fewer components, separation not required) – Redundancy for more probable failures – Automatic actuation with power from onsite diesels • Active Nonsafety Equipment Design – Reliable, experienced based, industrial grade equipment – Non-ASME, non-seismic, limited fire / flood / wind protection – Availability controlled by procedures, no shutdown requirements – Reliability controlled by maintenance program
Slide 34 Startup Feedwater System • Simplified, Reliable Non-Safety System – Auto start on low SG level with auto SG level control • Same flow if one or two pumps start • Operation does not cause excessive RCS cooldown or SG overfill – Auto load on non-safety DG – Simple reliable system design • Two electric motor pumps, no steam turbine driven pumps • No physical separation requirements – PRHR HX not actuated if SFW works as designed
Slide 35 AP1000 Startup Feedwater System
CONDENSATE TANK
FC
SG MFW A YARD
FC TURB M BLDG FC
M
FC SG B M
FC M
SFW PUMPS
IRC AUX AUX TURB BLDG BLDG BLDG
Slide 36 System Defense In Depth
• AP1000 Provides Multiple Levels of Defense – First actuation is usually nonsafety active system • High quality industrial grade equipment – Second actuation is safety passive system • Provides safety case for SSAR • Highest quality nuclear grade equipment – Other passive features provide additional levels of defense • Example; passive feed/bleed backs up PRHR HX – Available for all shutdown conditions as well as at power – More likely events have more levels of defense
Slide 37 AP1000 I&C Systems
• Control System – Plant wide non-1E system for all normal displays & controls – Microprocessor / software based, multiplexed communications • Safety System – Reduced size 1E system for all safety displays & controls • Use of passive systems eliminates many safety components – Microprocessor / software based, multiplexed communications – May use same hardware / software as Control I&C • Diverse System – Limited scope non-1E system, PRA based displays & controls • Backs up Safety I&C where common mode failure a risk – Different microprocessor & software than Safety I&C • No multiplexing
Slide 38 AP1000 Human-Machine Interface
• Compact Control Room – Designed for 1 Reactor Operator and 1 Supervisor • Displays – Plant status / overview via wall panel (non 1E) – Detail display via workstation video displays (non 1E) – Small number dedicated displays; safety (1E) & diverse (non 1E) • Controls – Soft controls (non 1E) for normal operation – Small number dedicated switches; safety (1E) & diverse (non 1E) • Advanced Alarm Management • No Paper Procedures
Slide 39 Main Control Room 3D Model
Slide 40 AP1000 Passive Safety System Design Improves Economics and Construction Schedule
50% Fewer 35% Fewer 80% Less 45% Less 70% Less Safety-grade Pumps Safety-grade Seismic Building Cable Valves Pipe Volume
Slide 41 Comparison of Seismic Category I Buildings
Slide 42 Modular Construction Allows More Tasks To Be Done in Parallel Result: Shorter Construction Schedule
Slide 43 Modules Designed into AP1000 from the Beginning
Pump/Valve Module Module Type Number Structural 122 Piping 154 Mechanical 55 Equipment Electrical Equipment 11 TOTAL 342
Raceway Module Structural Module Depressurization Module
Slide 44 New Reactor License Applications in U.S. (31 Currently Planned)
Slide 46 The Steps to Bring a New Plant On-line in 2016 (United States)
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4 Q 1 Q 2 Q 3 Q 4
FDA AP1000 DC
COL Engineering Submit COL COL Issued
FOAK Design Details
Procurement Activities
Site Preparation
Construction Commercial Operation Commissioning and Startup Testing
Slide 47 How AP1000 Reduces Risk
Slide 48 AP1000 … Ready for Commercialization • Meets Utilities’ Needs – Satisfies U.S. Utility Requirements • Provides New Standard of Safety – Simplified Passive Safety features • Major Simplifications Achieved – Construction, operation, maintenance • Licensing Certainty – Design Certification in Dec 2005 • More economical to build • Four units in construction in China, 2013 startup Ground Breaking of AP1000 in China • Two units contracted by Southern Co • Two units contracted by SCANNA
Slide 49 Questions
Slide 50